On Wed, 21 Mar 2007 07:41:46 -0700 (PDT) Christoph Lameter <[EMAIL PROTECTED]> wrote:
> On Wed, 21 Mar 2007, Eric Dumazet wrote: > > > In order to avoid a cache miss in kmem_cache_free() on NUMA and reduce hot > > path length, we could exploit the following common facts. > > > > 1) MAX_NUMNODES <= 64 > > MAX_NUMNODES == 1024 on IA64 and may be on x86_64 in the future. So what ? I am very happy for you Christoph. Average linux machines (ie more than 99.99 % on this planet) are using MAX_NUMNODES <= 64 If you read my patch, your lovely 1024 nodes machines will run as before : No change at all for big machines. > > > 2) alignment of 'struct kmem_cache *' can be >= 64 > > > > The following patch changes the page->lru.next to contain not only the > > 'struct kmem_cache *' pointer, but also the nodeid in the low order > > bits. > > Nack. > > I would suggest you audit slab and make sure that we never fall back and > always enter a slab on the node of page_to_nid(page). If > all allocations use GFP_THISNODE then you should be safe and then we can > remove the nodeid from the slab structure and simply use the available > node information in the page struct. > Last time I checked 'struct page', they was no nodeid in it. I cooked this patch because you told me it was possible to have a 'slab nodeid' different than page_to_nid(obj). Now you want me to prove the contrary. Me confused. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
